But in practice, a good one probably won't let anyone else sharpen their knives, nevermind be unable to do it.

It'd be a bit like 'someone else has set up a software development environment for you, now write some code' I suppose.

Good race car drivers actually know how car works and I bet can fix many things. Race car drivers take the car to the limit and understanding how car works is competitive advantage - they can help mechanics tune the car, can diagnose problems that show up only at high speed, understand pro/cons of different suspesions and how they work, etc.

On the other hand typical Uber driver does not need to know anything about the car other than what pedals are for and you turn the wheel to steer. If he tries to take the car to the limit, he probably gets 1 star rating from scared passenger. No need to know how car works.

You decide whether Google engineers are more like race car drivers or Uber drivers.